The healthcare provider prescribes 250 mL of 0.9%NaCl to infuse over 2 hours. The drop factor is 60 gtt/mL. How many gtts per minute? ______________ gtt/min. Round to the whole number."

By using a series of conversion factors, proportional fractions designed to convert units of measurement from one form to another.

250 mL of fluid infused over 2 hours is equivalent to 125 mL infused within 1 hour.

Now, the infusion rate of 125 mL per 1 hour is multiplied by the drop factor of 60 gtt per 1 mL as shown here:

[tex]\frac{125 mL}{1 hr} (\frac{60 gtt}{1 mL} )[/tex]

mL in both numerator and denominator will cancel each other out, leaving drops per hour (gtt/hr) as the remaining units.

125 x 60 = 7500, thus, what remains is 7500 gtt/hr

The denominator must reflect minutes, so in order to do so, the conversion factor of 60 minutes per hour must be multiplied in as shown here:

[tex]\frac{7500 gtt}{1 hr} (\frac{1 hr}{60 min} )[/tex]

hr in both numerator and denominator will cancel each other out, leaving drops per minute (gtt/min) as the remaining units.

7500 ÷ 60 = 125, thus what remains is 125 gtt/min

If 250 mL of 0.9% NaCl are prescribed to be infused over 2 hours at a drop factor of 60 gtt/mL, the pump should be set to infuse at a rate of 125 drops per minute, or 125 gtt/min.